Tension control apparatus

Abstract

A yarn tension control device for controlling the tension of yarn being longitudinally advanced having two movable yarn guide members with spaced guide pins alternately engaged by the longitudinally travelling yarn. One of the yarn guide members is pivotally mounted to move its guide pins across the yarn path and has a pin or roller mounted spaced from its pivot and is balanced by a balancing weight. A pivotally mounted control cam has a balancing weight and a laterally extending arm with a biasing weight adjustably positioned on the arm. The control cam has a cam profile in contact with the pin or roller on the first yarn guide member and the biasing weight biases this profile into engagement with the roller or pin to pivot the first yarn guide member in a desired direction. The portion of the arcuate cam profile nearest its pivot is concave, a middle portion thereof is nearly straight, and the portion of the cam profile furthest from the control cam pivot is convex. Thus as the first yarn guide member moves away from the second yarn guide member the biasing is decreased.

What is claimed is: 
     
       1. A yarn tension control device for controlling the tension of a running yarn comprising, first and second yarn guide members having yarn guide pins alternately engaged by traveling yarn, means mounting the first yarn guide member pivotally free to pivotably move rockably across the normal yarn path, means movably mounting the second yarn guide member, the first yarn guide member mounting a roller or pin spaced from the pivot thereof and a first balancing weight, a control cam pivotally mounted and having a second balancing weight and an extending arm, a third weight adjustably mounted on said extending arm, said control cam having a cam profile which contacts said roller or pin mounted on the first yarn guide member, and the third weight and said extending arm biasing said cam profile into engagement with said roller or pin to pivot the first yarn guide member in a desired direction. 
     
     
       2. A yarn tension control device as claimed in claim 1, wherein the nearest portion of said cam profile to the pivot of said control cam is concave, the middle portion of said cam profile is nearly straight, and the farthest portion of said came profile from said pivot of said control cam is convex, whereby as the first yarn guide member moves away from the second yarn guide member said biasing is decreased. 
     
     
       3. A yarn tension control device as claimed in claim 1, further comprising a stop for limiting the turning movement of the first yarn guide member. 
     
     
       4. A yarn tension control device as claimed in claim 1, wherein said means movably mounting the second yarn guide member comprises a movable support member.